Continuous method of preparing silver halide emulsions

ABSTRACT

Liquids which form a poly-phase system when mixed are mixed by means of forces creating turbulence therein, such as shearing forces created by rotating the walls of a mixing passageway at velocities sufficient for turbulent flow. Preferably the liquid contains dissolved reactants which react to form a dispersion in situ, such as a silver salt and a halide salt which react in aqueous solution to form a silver halide dispersion.

United States Patent [1 1 Claes CONTINUOUS METHOD OF PREPARING SILVER I-IALIDE EMULSIONS Frans Henri Claes, Edegem, Belgium Assignee: Agfa-Gevaert, Mortsel, Belgium Filed: Mar. 31, 1971 Appl. No.: 129,664

Inventor:

Foreign Application Priority Data Apr. 3, 1970 Great Britain 15948/70 US. Cl. 96/1l4.7, 96/94 Int. Cl G03c 1/02 Field of Search 96/94, 114.7, 94 R,

References Cited UNITED STATES PATENTS 12/1968 Frame 96/114.7

[4 1 Apr. 2, 1974 3,628,959 12/1971 Theilemann 96/94 3,503,712 3/1970 Sussman 23/253 FOREIGN PATENTS OR APPLICATIONS 787,336 12/1957 Great Britain 96/94 Primary Examiner--J. Travis Brown Assistant Examiner-Alfonso T. Suro Pico Attorney, Agent, or Firm-William J. Daniel [5 7] ABSTRACT 10 Claims, 29 Drawing Figures PATENTEUAPR 2 I974 I 3; 801326 snm n1 ur 26 FIG 1 FIG 2 FIG 4 ATENTEDAPR 2 I974 sum 02 or 26 FIG 5 IAIENIEDAPR 21914 3.801.326

saw on or 26 FIG 7 wamnm 2mm 3,801,326 sum WM 26 PATENTED APR 2 I974 sum 0 0F 2s Fig. 13

PATENTED AFR SHEET 11 0F 26 Fig. 74

minimum 2mm 3801.826

' sum 13UF 26 Fig. 16

wamemm 2mm 3.801326 SHEET 1n HF 26 NENTEDAPR 2 I974 DON 1 DOM PATENTEDAPR 2 m4 SHEET 15 HF 26 QOm PATENTEDAPR 21914 SHEET 17 0F 26 ON 0E mop PATENTEUAPR 21914 3.801.326

sum 19 [1F 25 Fig. 22 

2. A method of mixing according to claim 1 wherein said layer space is defined by the mutually facing surfaces of two discs at least one of which is rotated about its axis with respect to the other to produce said rotational movement and said solutions are introduced generally at the locus of the disc axis and discharged at their outer periphery.
 3. A method of mixing according to claim 1, wherein the passageway has a transverse cross-sectional dimension of less than 5 mm.
 4. A method of mixing according to claim 1, wherein the passageway is a layer space defined by the surfaces of walls, which are continuously relatively rotated about an axis for generating such frictiOnal forces.
 5. A method of mixing according to claim 1, wherein the colloid is gelatin.
 6. A method of mixing according to claim 1, wherein the formation of the silver halide grains in said passageway proceeds in the presence of a grain growth restrainer.
 7. A method of mixing according to claim 4 wherein said layer space is in the form of an annular layer space defined by mutually facing coaxial surfaces of revolution extending at an angle other than perpendicular to the axis of rotation.
 8. A method of mixing according to claim 4 wherein said passageway gradually tapers toward said other end.
 9. A method of mixing according to claim 8 wherein said passageway is defined by the annular clearance space between an inner rotor and an outer housing surrounding the rotor in closely spaced coaxial relation, said clearance space continuously decreasing in its radial dimension, the larger end constituting the inlet to said passageway and the smaller end as the outlet therefrom.
 10. A method of mixing according to claim 1 wherein the formation of the silver halide grains proceeds in a reaction medium having a pAg in the reaction mixture of about 2.5-3.5 or about 7.5-8.5. 